You might check the carburetor mixture adjustment while you are at it. Carefully note where the screw slot is pointing, then turn it clockwise gently until it bottoms lightly, noting how far it turns. (Should be about 1.5 turns.) Then put it back where it was, and see if it runs better slightly leaner or richer. Turn it clockwise an eighth of a turn and listen to the exhaust smoothness. If it is still just as smooth, go another eighth of a turn. Repeat until you notice it slow down slightly, or perhaps hunt (cycle in speed). That is the lean limit. Turn it anticlockwise in eighth turn steps until it starts to slow down. That is the rich limit. Set it halfway between lean and rich limits.
